#include <unistd.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>


void sig_usr(int singo) {
	printf("received signal %d\n", singo);
}

int main(void) {
	if (signal(SIGINT, sig_usr) == SIG_ERR) {
		printf("error signal, arg=SIGUSR1\n");
		return 1;
	}
	for (;;)
		pause();
}